Rapid Detection by Genomic Amplification of Loofah Witches’ Broom Phytoplasma in Leafhopper Vectors

Loofah (Luffa cylindrical) is a common vegetable crop in Taiwan and other Asian countries. Reported here is a novel rapid approach for detecting loofah witches broom (LfWB) phytoplasma in single leafhoppers. Field samples of suspected diseased plants and potential vectors from southern Taiwan were processed to test for the presence of the LfWB phytoplasmas using both strain-specific DNA hybridization (DH) and polymerase chain reaction (PCR) assays. The commonest pathogen causing loofah disease in southern Taiwan is LfWB phytoplasma. Leafhoopers collected at nine locations near LfWB-infected plants were found to be positive for LfWB by PCR⁄DH at an incidence of 28.5–40.0%. Of the different leafhopper species tested, only Hishimonus concavus was positive for LfWB, suggesting that H. concavus is a natural vector of LfWB in Taiwan. Using our proposed primers in this PCR assay, a single LfWB-infected leafhopper can be detected rapidly and directly